I. Field of the Invention
The present invention relates to railroad cars having bottom discharge hopper-type bodies in which the hoppers are closed by horizontally disposed gates that are displaced laterally to open and close by drive systems that include a rack and pinion drive mechanism operated by rotating an associated operating rod using attached capstans. More particularly, the invention relates to a mechanism for externally gripping and rotating the handles or capstans of operating rods of such systems.
II. Related Art
A railroad car hopper discharge unit typically attaches to the bottom of a railroad car hopper and includes straight sidewalls and sloping end walls which terminate in horizontally directed flanges which, in turn, define a rectangular outlet opening. Provision is made for the attachment of gate assemblies for each of the hoppers of a railcar for selective discharge of commodities contained in the car body. The sliding gate discharge system includes a gate that is moved between fully open and fully closed positions by the operation of a rack and pinion system operated by rotating a shaft or operating rod connected to rotate one or more pinion gears, to thereby laterally displace an associated rack and with it the associated gate. Typical systems of the class described are shown in U.S. Pat. Nos. 4,450,773; 4,342,267; and 6,363,863.
The gate is operated by a drive mechanism that includes an elongated operating rod which carries one or more pinion gears and which is supported by the frame of the gate assembly, the rotation about its axis which is fixed relative to the gate assembly frame. The rack and pinion, of course, converts the rotary movement of the operating shaft into linear fore and aft movement to operate the hopper gate. Each operating rod extends laterally outward beyond the gate operating assembly and is provided with an operating handle or capstan at one or both ends fixed to the operating rod. Each capstan is provided with shaped outward directed recess adapted to receive a mechanized operating tool adapted to address the handle from track side and rotate the operating shaft utilizing the shaft handle to open and close the gate mechanism.
One particularly prevalent and undesirable problem with such systems has to do with internal wear to the rod handles or capstans themselves. Because debris can accumulate in the rack and pinion systems and because of the generally heavy nature of the equipment, it is often difficult to rotate the operating shafts, particularly in the case of opening gates of loaded cars. Repeated torque often causes the initially square operating recess openings in the capstans (see FIG. 2) to become rounded such that corresponding conventional square shaped mechanized tools are no longer able to operate the gate mechanisms. The operating rods must be operated manually by using bars to address side openings or the capstans must be replaced. Thus, there remains a definite need for an improved system for rotating the operating rods of discharge gate systems of the kind described which prevents eventual stripping of the keyway or other such problems.
By means of the present invention, there is provided a tool for rotating capstans associated with the operating shafts of railroad car discharge gate mechanisms which avoids problems associated with previous devices. The mechanized device of the present invention includes a compact hydraulic gripper mechanism that grabs the outside of the capstan to insure positive rotation without the need for keying a tool into a shaped opening in the laterally directed end of a capstan. The mechanical system of the invention includes a cylinder-operated gripper having a plurality, preferably a pair of spaced, converging, opposed gripping fingers with teeth that converge to grab the outside of the capstan and thereafter the gripper rotates to operate the gate mechanism. The gripper is mounted from one end of a gripping shaft having a hollow or recess at the other end to receive a piston rod associated with a fluid cylinder as an extension of the cylinder rod. The end of the gripper shaft is preferably fixed to the cylinder rod so that both rotate together. The gripper shaft is further mounted within and keyed to a gripper shaft sleeve member mounted within and keyed to rotate with the hollow shaft of a low speed, high-torque hydraulic motor which is used to rotate the gripper and piston relative to the cylinder and which presents a highly efficient compact design.
Spaced gripper default rollers are mounted on a base plate behind respective gripper fingers flanking the gripper shaft such that retraction of the piston rod of the fluid cylinder causes the default rollers to force the gripper fingers to close and extension of the cylinder rod allows them to open. Tension members are provided to hold the gripper fingers open against the default rollers in a normally open posture.
The gripper fingers are designed to enclose any sized capstan from any angle and, of course, have the ability to rotate the capstan in either direction to thereby open or close the discharge gate as desired. In this manner, the reciprocal action of the gripper cylinder opens and closes the gripper fingers and the rotation of the hydraulic motor enables the gripper to rotate a captured device.
The system can also be stopped at any point to enable the partial opening of the discharge gate. The tool assembly is adapted to be mounted on a conventional dolly associated with prior capstan rotating tool systems. The dolly is designed to operate parallel to the railcars along the side of the track located in a grain terminal or other unloading station and includes an extendable platform to move the gripping mechanism laterally to approach a capstan of interest.